From: Mark Grant (mark@unicorn.com)
Date: Sun Jul 20 1997 - 08:18:09 MDT
On Thu, 17 Jul 1997, Michael Lorrey wrote:
> I've never worked on a biplane, but I do know that business jets take a
> good multiple of the maintenance time of small props planes. Rebuilding
> a turbine engine is a lot tougher than a piston engine.
Aha... this may explain our difference of opinion. You're talking purely
about the amount of time required for maintenance when it's neccesary,
whereas I'm talking about the frequency of maintenance and the frequency
of failures.
Sure, major maintenance on a more complex plane is going to be more
complex and time-consuming, but from what I remember Bach's books he'd get
up in the morning for an hour or two of maintenance on his biplane and
even then every few weeks the engine would fail for some reason and he'd
have to make an emergency landing. In comparison, he'd jump into his jet
(T-38?) to fly between Florida and California with only a cursory
preflight check; and it never crashed. In both cases they had major
maintenance every once in a while, which would be much more work for the
jet than the biplane.
So complexity may increase the effort required to maintain an aircraft,
but has little bearing on reliability. And since much of that maintenance
involves taking things off, looking at them, and putting them back on,
built-in nanosensors could eliminate most of that.
> You can sheild a large part of it, but you are going to preserve the
> areas of greatest sheilding for your crew, and with a mid course
> turnaround, you've gotta have two sheilds, unless you can unhitch from
> it and turn around and rehitch to the sheild at midcourse.
You missed the point; the shield is just supposed to be a big hunk of junk
which flies along in front of your ship and erodes when hit. But you're
right; you would have problems holding it in place while braking. I guess
you'd just rely on the exhaust from your engines vaporising anything small
before it hit you; if you hit anything big you're dead anyway, shield or
no shield.
> Once they brought it back due to a broken toilet.
Can you cite a mission number, because I don't remember that. I have vague
memories of coming back early because of a blocked water dump valve, but
that was a problem because the fuel cells need to dump water overboard,
not because it affected the toilet.
> The point is that things break more often than not with the shuttle,
> even though it was custom built and is basically rebuilt after every
> mission, and it only flies one week missions.
Sure, but that's due to government designs, not an inherent problem with
spacecraft (BTW, wasn't the last shuttle flight over two weeks?). And it
still doesn't affect the fact that the majority of maintenance is fixed
regardless of flight time. If a fuel cell breaks or a valve blocks up you
just tear it out and fit a new one; that may require a few hours of
overtime, but it's nothing compared to overhauling the engines.
Mark
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